Highly porous carbon with selective transformation of nitrogen groups boosts the capacitive performance through boric acid template assisted strategy

Abstract

To address the extensive demand for energy storage, the development of unique carbon-based supercapacitors represents a viable solution. We successfully synthesize the unique boron (B), nitrogen (N)-containing porous carbon (denoted as BNPC) from reed biomass through one-step boric acid templated carbonization method, which are used as high-performance carbon electrode for electric double-layer capacitor (EDLC). By the synergistic effects of boric acid template and N-rich melamine, a well-balanced micro‐/meso-porous structure and abundant N and oxygen (O) heteroatoms within BNPC are readily obtained, exhibiting an ultrahigh specific surface area of 2619 m2·g−1. These distinctive natures endow BNPC electrode with the excellent capacitive behaviors, affording an outstanding specific capacitance of 396.8 F·g−1 at a three-electrode (3E) system with KOH electrolyte. Density functional theory (DFT) method is utilized to further clarify the interaction mechanism between K and designed graphene with various N configurations, revealing the significant roles of Pyridinc-N and Graphitic-N. The two-electrode (2E) symmetric supercapacitor assembled by BNPC electrodes in TEABF4 electrolyte demonstrates an extremely high energy density of 51.82 Wh·kg−1 at a power density of 375 W·kg−1 and great capacitance retention of 91 % after 6000 cycles. This reed-derived highly porous carbons display superior electrochemical performance, making it the ideal candidates for large capacity supercapacitors in practice.